NFS CTO semantics require that (absent a delegation) the server must be contacted at each open. nfs_lookup_verify_inode() implements this when the dcache contains a positive cached entry. However it is not called when the dcache contains a negative cached entry. That path uses nfs_neg_need_reval() which doesn't impose CTO semantics. So a sequence like: rm -f testfile ls -l testfile ssh $server touch testfile cat testfile will fail: cat: testfile: No such file or directory an 'strace' will confirm that this resulted from an 'open' system call. So add code to nfs_neg_need_reval implement CTO semantics much like that in nfs_lookup_verify_inode(). Signed-off-by: NeilBrown <neilb@xxxxxxx> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index d9f3d067cd15..f8022da72460 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1062,6 +1062,8 @@ int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, /* Don't revalidate a negative dentry if we're creating a new file */ if (flags & LOOKUP_CREATE) return 0; + if ((flags & LOOKUP_OPEN) && !(NFS_SERVER(dir)->flags & NFS_MOUNT_NOCTO)) + return 1; if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) return 1; return !nfs_check_verifier(dir, dentry);
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